检索结果-南通市图书馆

Structural Durability & Health Monitoring 2025年第1期19卷 55-75页

作者： Zhenyu Zhang Quan Jin Haitao Zhang Zhao Liu Yuyang Wu Longfei Zhang Renzhang Yan cccc Third Highway engineering co. Ltd.Beijing101300China School of Civil engineering Chongqing Jiaotong UniversityChongqing400074China

When the upper chord beam of the beam-string structure(BSS)is made of co.crete-filled steel tube(CFST),its overall stiffness will change greatly with the co.struction of co.crete placement,which will have an impact on the design of the tensioning plans and selection of co.trol measures for the *** order to accurately obtain the bending stiffness of CFST beam and clarify its impact on the mechanical properties of co.posite BSS during co.struction,the influence of some factors such as height-width ratio,wall thickness of steel tube,elasticity modulus of co.crete,and friction co.fficient on the bending stiffness are analyzed parametrically by the numerical simulation technology based on an actual *** calculation formula of the equivalent bending stiffness of CFST is also established through mathematical statistical ***,the equivalent bending stiffness is introduced into the co.struction and use stages of the co.posite BSS,respectively,and the mechanical properties such as prestress-tensioning co.trol value,structural deformation,and internal force of key members are co.paratively analyzed when adopting two different co.struction ***,the optimal co.struction plan of co.crete placement first and then prestress-tensioning is proposed.

关键词： co.crete panels freeze-thaw damage co.pression-shear crack tension-shear crack

TIME-DOMAIN RESPONSES OF IMMERSING TUNNEL ELEMENT UNDER WAVE ACTIONS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2009年第6期21卷 739-749页

作者： CHEN Zhi-jie WANG Yong-xue WANG Guo-yu HOU Yong State Key Laboratory of co.stal and Offshore engineering Dalian University of Technology Dalian 116024 China cccc-fhdi engineering co. Ltd Guangzhou 510230 China

The time domain responses of the tunnel element under wave actions during its immersion are investigated based on the linear wave diffraction theory. The integral equation is derived by using the time-domain Green function that satisfies the free water surface co.dition in the finite water depth, and is solved by the boundary element method. The motion equations of the tunnel element are solved by the fourth order Runge-Kutta method. A co.parison between the co.puted and measured results reveals that the numerical model can effectively simulate the motion responses of the tunnel element and the cable tensions when the motions of the tunnel element are within some limit. Taking the tunnel element of 100 m in length, 15 m in width and 10 m in height as an example, the co.putational results of the motion responses of the tunnel element and the cable tensions in different immersing depths are obtained under different incident wave co.ditions.

关键词： Immersed tunnel time-domain response cable tension boundary element method

Stress Reco.ery Procedure for the Bonded Particle Model

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2021年第3期34卷 356-368页

作者： Ruoyu Guan Shean Bie Canpeng Chen State Key Laboratory of Hydraulic engineering Simulation and Safety School of Civil EngineeringTianjin UniversityTianjin 300072China cccc-fhdi engineering co. Ltd.Guangzhou 510230China

In the simulation of disco.tinuous block systems,the discrete element method(DEM)has better co.putational efficiency and co.vergence than the finite element method(FEM).When several DEM particles are bonded together with parallel bonds(the bonded particle model,BPM),various shapes and block fractures can be *** main aim of the BPM is to simulate a co.tinuous material in which the stress distribution is *** the existing stress result for a single particle is an average value over the particle’s area,stress results do not exist in the area between *** this paper,the stress value for a single two-dimensional DEM particle is deduced.A stress reco.ery procedure with a linear stress function for a triangular element generated by the centroids of three bonded particles is *** this way,the reco.ered stress field for the whole mesh co.posed of all triangular elements is co.tinuous.A stress gradient exists in the whole *** can also provide more accurate stress values for judging a fracture inside a *** and asymmetrical models are simulated by the BPM and *** to the FEM results,the reco.ered stress results for the BPM can describe the stress distribution in the simulated co.tinuous *** the model with the theoretical stress solution,the reco.ered result and the theoretical solution co.ncide well.

关键词： Discrete element method Bonded particle model Stress reco.ery procedure co.tinuous stress field

Seismic response analysis of road vehicle-bridge system for co.tinuous rigid frame bridges with high piers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earthquake engineering and engineering Vibration 2012年第4期11卷 593-602页

作者： Li Yongle Chen Ning Zhao Kai Liao Haili Department of Civil engineering Southwest Jiaotong University cccc Highway co.sultants co. Ltd.

The objective of this study is to investigate the effects of earthquakes on road vehicle-bridge co.pling vibration systems. A two-axle highway freight vehicle is treated as a 13 degree-of-freedom system co.posed of several rigid bodies, which are co.nected by a series of springs and dampers. The framework of the earthquake-vehicle-bridge dynamic analysis system is then established using an earthquake as the extemal excitation. The equivalent lateral co.tact force serves as the judgment criteria for sideslip accidents acco.ding to reliability theory. The entire process of the vehicle crossing the bridge is co.sidered for a very high pier co.tinuous rigid frame bridge. The response characteristics of the vehicle and the bridge are discussed in terms of various parameters such as earthquake ground motion, PGA value of the earthquake, incident angle, pier height, vehicle speed and mass. It is found that seismic excitation is the most influential factor in the responses of the vehicle-bridge system and that the safety of vehicles crossing the bridge is seriously impacted by the dual excitations of earthquake and bridge vibration.

关键词： vehicle-bridge system co.pling vibration seismic effects safety dynamic response

Hurricane damage assessment for residential co.struction co.sidering the non-stationarity in hurricane intensity and frequency

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2016年第12期35卷 110-118页

作者： WANG Cao LI Quanwang PANG Long ZOU Aming ZHANG Long Department of Civil engineering Tsinghua University cccc Highway co.sultants co. Ltd.

Natural hazards such as hurricanes may cause extensive eco.omic losses and social disruption for civil structures and infrastructures in co.stal areas, implying the importance of understanding the co.struction performance subjected to hurricanes and assessing the hurricane damages properly. The intensity and frequency of hurricanes have been reported to change with time due to the potential impact of climate *** this paper, a probability-based model of hurricane damage assessment for co.stal co.structions is proposed taking into acco.nt the non-stationarity in hurricane intensity and frequency. The nonhomogeneous Poisson process is employed to model the non-stationarity in hurricane occurrence while the non-stationarity in hurricane intensity is reflected by the time-variant statistical parameters(e.g., mean value and/or standard deviation), with which the mean value and variation of the cumulative hurricane damage are evaluated explicitly. The Miami-Dade co.nty, Florida, USA, is chosen to illustrate the hurricane damage assessment method proposed in this paper. The role of non-stationarity in hurricane intensity and occurrence rate due to climate change in hurricane damage is investigated using some representative changing patterns of hurricane parameters.

关键词： hurricane damage assessment intensity frequency non-stationarity climate change

Sulphate attack resistance of high-performance co.crete under co.pressive loading

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & engineering) 2013年第7期14卷 459-468页

作者： Hui XU Yu-xi ZHAO Lei CUI Bi XU Institute of Structural engineering Zhejiang University School of Civil engineering Newcastle University cccc Tianjin Dredging co. Ltd.

In this paper, an experimental study on the sulphate attack resistance of high-performance co.crete (HPC) with two different water-to-binder ratios (w/b) under co.pressive loading is presented. The sulphate co.centration, co.pressive strength, and the mass change in the HPC specimens were determined for immersion in a Na2SO4 solution over different durations under external co.pressive loading by self-regulating loading equipment. The effects of the co.pressive stress, the w/b ratio, and the Na2SO4 solution co.centration on the HPC sulphate attack resistance under co.pressive loading were analysed. The results showed that the HPC sulphate attack resistance under co.pressive loading was closely related to the stress level, the w/b ratio, and the Na2SO4 solution co.centration. Applying a 0.3 stress ratio for the co.pressive loading or reducing the w/b ratio clearly improved the HPC sulphate attack resistance, whereas applying a 0.6 stress ratio for the co.pressive loading or exposing the HPC to a more co.centrated Na2SO4 solution accelerated the sulphate attack and HPC deterioration.

关键词： Sulphate attack resistance High-performance co.crete (HPC) co.pressive loading

Intelligent feedback analysis on a deep excavation for the gravity anchorage foundation of a super suspension bridge

在线全文

学校读者我要写书评

暂无评论

岩石力学与工程学报 2019年第A01期38卷 2898-2912页

作者： RAN Tao LIU Daan MEI Songhua WANG Weiwei TAN Lihua Institute of Geology and Geophysics Chinese Academy of Sciences University of Chinese Academy of Sciences Zhongnan engineering co. Ltd. cccc First Highway engineering co. Ltd.

In order to ensure the co.struction safety of the 38.5 m deep excavation for the gravity anchorage foundation of Fuma Yangtze River Bridge, an intelligent feedback analysis was applied to this excavation project. First, a three-dimensional numerical model that simulating the co.struction process of the excavation was built,and the deformations of the supporting structures were calculated by the finite difference program FLAC3 D. Then,the non-linear mapping relationship between the geomechanical parameters and the excavation-induced displacements was established by the back-propagation neural network(BPNN). Last,the geomechanical parameters were optimized intelligently by the genetic algorithm(GA) based on the developed BPNN model and the measured displacements,and the deformations during the subsequent excavation stages were predicted based on the back-calculated parameters. The research results showed that:the back-calculated values of E1,μ1,c1,and φ1 of the co.pletely weathered stratum,and E2 of the heavily weathered stratum were greater than the initial values,while the inversion value of E3 of the moderately weathered stratum was smaller than the initial value. The magnitudes and the variation tendencies of the predicted displacements were in good acco.dance with the measured displacements. At the end of the excavation,the retaining piles and the top beams had a maximum displacement of 15–20 mm,exhibiting a quite small magnitude as co.paring with other case histories. Local co.centration of shear stress mainly occurred at the soil-pile interface and at the toe of the excavation slope,and the plastic zones mainly appeared in the co.pletely weathered stratum. After the co.pletion of the excavation,there were no yielding elements in the model,and the co.vergence of the numerical co.putation was achieved,indicating the excavation was in a stable state. This study lays the basis for the subsequent co.struction and operation of the bridge,and offers a significant refe

关键词： foundations suspension bridge anchorage deep excavation parameter inversion deformation prediction intelligent feedback analysis

Performance of a deep excavation and the influence on adjacent piles:A case history in karst region co.ered by clay and sand

在线全文

学校读者我要写书评

暂无评论

Underground Space 2023年第1期8卷 45-60页

作者： Yubing Yang Caiyuan Chen Chao Liu Longtian Huang Wei Chen Nengyou Lin Jie Cui Wandong Xie co.lege of Water co.servancy and Civil engineering South China Agricultural UniversityGuangzhou 510642PR China School of Civil engineering Guangzhou UniversityGuangzhou 510006PR China Architectural Design and Research Institute of Guangdong Province Guangzhou 510010PR China cccc–fhdi engineering co. LtdGuangzhou 510290PR China

This paper presents a case study of deep excavation adjacent to an existing bridge in karst region of Guangzhou city,*** movements of retaining structures,settlements of surrounding ground and pipelines,and the responses of bridge piles were measured and evaluated.A sudden surge of groundwater was reco.ded at the north pit when excavated ***-cement co.umns using the Metro Jet System(MJS)method was employed along the outer perimeters of the diaphragm wall where water inflow occurred,for the sake of blocking the flow *** measured maximum wall deflection dhm in this case ranged from 0.13%H to 0.3%H,with a mean value of 0.2%H(H is the excavation depth),which agreed well with the empirical prediction in mixed *** the MJS treatment,the wall and surrounding soils experienced notable lateral deflection and *** bridge piles experienced significant settlement since the excavation co.menced,which might be attributed to the inherent deficiency in geological co.dition and pile *** soil disturbance induced by the adjacent deep excavation accelerated bridge *** finite element analysis revealed that the excessive settlement of the bridge piles and ground surface resulted from co.fined-water withdrawal in sand layers.

关键词： Deep excavation MJS treatment Pile-foundation Karst region co.fined-water

Multi-objective and multi-scheme research on water and sediment regulation potential of reservoirs in the upper Yellow River

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2023年第2期38卷 203-215页

作者： Tao Bai Jia Yu Wenting Jin Jiaquan Wan Shaojie Gou Xu Ma Panpan Ma Xi'an University of Technology Ankang University Chengdu engineering co. Ltd. cccc First Highway co.sultants co. Ltd.

The problems of the deteriorating relation between water and sediment, and the escalating co.flict between water supply and demand in the upper Yellow River(YR), need to be addressed. Reservoirs of Longyangxia, Liujiaxia, and Heishanxia(Long-Liu-Hei) in the upper YR are taken as the research object, and a multi-objective, water-sediment optimal operation model for cascade reservoirs Long-Liu-Hei has been developed. This operation model co.siders the co.prehensive requirements of water supply, power generation, flood co.trol, and especially, water and sediment regulation. The improved Non-dominated Sorting Genetic Algorithms(NSGA-II) method is used to demonstrate the water and sediment regulation potential of three scenario schemes under long-term co.ditions, and the adjustable water allocation of four schemes under typical year co.ditions are calculated. It is reco.mended to use the mode of generating hydropower depending on the available water amount as the best operating mode under the co.ditions of a long time series and for typical years. This reco.mended operation mode has verified the rationality and accuracy of the reservoir operations *** the same time, co.pared with the calculation results for water and sediment regulation after the co.struction of the Heishanxia, the current research indicates:(1) Under the reco.mended model, the potential for water and sediment regulation under the long-term series and typical years is once every four years.(2) Inter-basin water transfer greatly improves the cascade power generation. When the adjustable water volume is co.verted into the co.trolled volume for water and sediment regulation,the intensity frequency of water and sediment regulation of cascade reservoirs are improved.(3) With the intensification of the co.tradiction between the supply of and demand for water resources in the upper YR in the future, the amount of transferable water exhibits a decreasing trend, and the regulation of water and sediment in th

关键词： Water and sediment regulation Multi-objective regulation Cascade of reservoirs Regulatory potential

P波斜入射形成的动应力路径及影响因素分析（英文）

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & engineering) 2017年第10期18卷 776-792页

作者： Bo HUANG Qi-qun LI Dao-sheng LING Jing-wen LIU Yu WANG Institute of Geotechnical engineering Zhejiang University MOE Key Laboratory of Soft Soils and Geoenvironmental engineering Zhejiang University cccc-fhdi engineering co. Ltd.

目的:研究P波斜入射下的地基动应力路径,探讨其影响因素和可能变化范围,为进一步研究斜入射地震波作用下场地动力响应奠定理论基础。创新点:1.从数学上证明斜入射P波在任一深度的地基中形成的应力路径在剪应力分量(偏差正应力-水平剪应... 详细信息

目的:研究P波斜入射下的地基动应力路径,探讨其影响因素和可能变化范围,为进一步研究斜入射地震波作用下场地动力响应奠定理论基础。创新点:1.从数学上证明斜入射P波在任一深度的地基中形成的应力路径在剪应力分量(偏差正应力-水平剪应力)组成的平面中为一个斜椭圆;2.分析了P波入射角、土体泊松比和单位波长深度对斜椭圆应力路径形状与大小的影响。方法:1.基于半无限弹性空间的地震波传播理论,考虑地震波在自由界面的反射,推导土体中任一深度处由P波斜入射产生的动应力,并表示成由剪应力分量组成的平面下的应力路径(公式(9))及该应力路径的特征参数表达式(公式(A12)^(A14));2.通过控制变量法,分析参数敏感性(图7、9、10和12)。结论:1.虽然证实P波斜入射引起的应力路径为斜椭圆形式,但在地基深度、入射波频率和波速的特定组合下,斜椭圆仍可从斜线一直变化到圆形,形式较为多样化;2.P波斜入射角度在30?~60?时引起的动偏应力幅最大,最大可达同等条件下其它入射角产生的动应力幅的2倍以上;3.斜入射角大于45?后,斜椭圆路径形状几乎不随入射角改变,在研究范围内以竖直扁椭圆形为主;4.土体饱和度大于70%时,泊松比的变化对土体斜椭圆路径形状影响不大,但动应力幅随泊松比增大而显著降低。

关键词：近场地震 P波斜入射弹性半空间动应力路径